Apparatus for heat-sealing metallic liners in containers



Aug. 11, 1959. 2,898,974

G METALLIC LINERS IN CONTAINERS J. 5. WILSON APPARATUS FOR HEAT-SEALINFiledMay 28, 1957 2 Sheets-Sheet 1 5 & v w

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. ATTORNEYS APPARATUS FOR HEAT-SEALING METALLIC LINERS IN CONTAINERSFiled May 28. 1957 J; B. WILSON Aug. 11, 1959 2 Sheets-Sheet 2 INVENTORJOHN B. W/LSO/V BY I ATTORNEYS United States Patent APPARATUS FORHEAT-SEALING METALLIC LINERS IN CONTAINERS John B. Wilson, Louisville,Ky., ,assign'or to Reynolds Metals Company, Richmond, Va., a corporationof Delaware Application May 28, 1957, Serial No. 662,140 9 Claims. (Cl.154- 1) installing of the liner.

While various forms of apparatus have been employed heretofore forheat-sealing particular non-metallic liners to the interior ofcontainers by employment of both heat and pressure, difficulty has beenencountered when attempting ,to use such apparatus for securing metallicliners in those containers. Such diiliculties frequently include thegalling of the thin metallic surface when removed from pressure contactwith a heated metallic mandrel, the non-uniformity of the seal of theliner to itself, or of the liner to the container wall, and thewrinkling of the liner during the sealing operation. It is these andsimilar disadvantages of the known procedures which it is a purpose ofmy invention to overcome.

An object of the invention is to provide an improved apparatus forsecuring a metallic liner preform to a container.

Another object is to provide an improved apparatus for applying sealingpressureto a metallic liner preform disposed in contact vwith theinterior of a container.

Another object is to provide an improved heat-sealing mandrelincorporating a means for stripping a lined container therefrom.

A further object is to provide an improved means for actuating a movableheat-sealing mandrel and for automatically retracting the, mandrel to acontainer receiving and discharging position.

Other objects and advantages will become apparent as the descriptionproceeds and when considered in conjunction with .the accompanyingdrawings in which:

Fig. l is a perspective view of one form of heat-sealing apparatus innormal position prior to use;

Fig. 2 is a diagrammatic view showing a liner preform in position uponthe mandrel;

Fig. 3 is a diagrammatic view showing the liner preform and container inposition upon the mandrel;

Fig. 4 is a longitudinal sectional view through the mandrel;

Fig. 5 is a sectional view on line 55 of Fig. 4;

Fig. 6 is a perspective view of the apparatus at an intermediate stageof operation;

Fig. 7 is a perspective view of the apparatus at another intermediatestage of operation and with all contacting sealing surfacessimultaneously in operation;

Fig. 8 is a developed view of a portion of an improved metallic linerwith a portion of the line-embedded metallic foil being shown; and vFig. 9 is a sectional view on line 9.-9-of Fig. 8 and to a greatlyenlarged scale.

In accordance with my invention, I arrange, either manually orautomatically, an unsealed metallic liner preform upon a metallicmandrel which is adapted to be 2,898,974 Patented Aug. 11, 1959 iceheated and ,with .themetallicsurface of thatliner in contact with themetallic mandrel. A container to which the liner is to .be sealedissthen disposed in surrounding relation to the liner preform. Thecontainer and liner are clamped together against the mandrel, preferablyalong the side of the liner which is to be sealed to itself, as well asto the container and this clamping pressure 'is maintained until thesealingoperationis completed. The mandrel with the liner and containerin place is then moved to successive positions against pressure applyingmembers which seal the liner to the container, except at one .open end.Upon completion of the sealing operation, the mandrel is retracted to adischarge and loading position, at which timethe lined container isremoved and a new preform and detached container is subsequentlyinstalled on the mandrel.

While the invention in its broader aspects is adapted for heat-sealingnon-metallic liners or liners of various metallic materials tocontainers, I prefer to employ the improved liner comprising an aluminumfoil layer laminated with a microcrystalline wax layer to a layer oftissue paper and known by the trademark Reyseal and as disclosed'morefully in the copending application of Raymond E. Jacke, Serial No.638,016, filed February 4, 1957, andassigned to Reynolds Metals Company.Referring now to Figs. 8 and 9, the liner designated generally at10-preferably comprises a rectangular shaped, laminated sheet 'having onone side a thin sheet 11 of metallic-foil, preferably aluminum, and onthe other side a somewhat thicker sheet 12 of a porous material, such astissue paper. A centrally located layer 13 of a heat sealingcomposition, such as a micro-crystalline wax is providcd between sheets11 and 12. Accordingly, when heat is applied to the liner, the wax tendsto flow through the tissue sheet and to become available for bonding toa surface in contact therewith. However, since it is desirable, if-notessential, in some usages of lined containers to have the metallic sheet11 bonded to itself along side and end seals, I also provide for passageof the wax through the otherwise impervious metallic sheet 11. Thispreferably is accomplished by lightly puncturing the sheet 11 alongperipheral edges, as seen at the bands 14, 15 and 16, as by passingthereover an abrading means, such as a rouletting wheel, or rollercovered with emery cloth, or the like, while under sufiicient pressureto form bands of spaced pin-holes of sufficient size to permit theheated wax'to exude therethrough for sealing purposes.

Furthermore, due to the tendency of the thin metallic sheet 11 to beabraded or galled by moving contact with a heated metallic mandrel,wrinkling of the metallic sheet, or wear thereof, .or both, may occur inmanufacture of the lined container unless provision is made to overcomethe same. As taught by the Jacke invention, these disadvantages may beovercome byline-embedding the metallic sheet into the layer of waxtherebeneath. As seen in Figs. 8 and 9, a series of closely spacedparallel small grooves 17 are formed in one direction across the entireouter surface of sheet 11, these grooves being intersected by a similarseries of grooves 18 at a suitable intersecting angle'thereto; Astherespective grooves 17 slipping characteristics .arefound when motionoccurs between thatshcet and the surface of a metallic mandrel.Moreover, expansion of themetallic. sheet due to heating can take placewithout warping or wrinkling of the surface of the sheet as a whole.

With the foregoing in mind, an unsealed liner perform of the describedReyseal material and generally shown at 21 in Figs. 2 and 3, upon beingsuitably folded by any conventional folding apparatus, is adapted forpositioning endwise upon mandrel 22, later to be described. It will beunderstood that in this folding operation, one end of liner projectsaxially of the liner preform to form an open end which may slip snuglyupon the mandrel, the other end of that liner having band folded uponitself, and the sides of that liner having bands 14 and 16 folded uponthemselves in interlocked arrangement as shown by said Jackeapplication. Thus, as seen in Fig. 2, the tissue lamination of the lineris exteriorly exposed and the metallic side 11 of the liner is incontact with the mandrel.

The side seal of the preform is in general the most important seam toseal, since it must sustain bulging stresses of the filled container andis usually extended over the end portion of the container as seengenerally at 24 in Fig. 2. As an important feature of the invention,this side seal is disposed on the side of the mandrel which is toreceive a prolonged and uninterrupted pressure.

Following positioning of the unsealed, folded preform upon the mandrel,a conventional container 23, open at one end and sealed at its sides andother end, is positioned over the preform in substantially envelopingrelation thereto and with its inner surface in contact with the tissuelayer 12 of that preform. This container may be of any suitable materialto which the liner will adhere, but I prefer to use a conventionalcardboard container.

Reference now is made to Fig. 1 showing one form of apparatus embodyingthe invention and adapted for efficiently lining the container abovementioned. While the apparatus is shown detached from the means forfolding the preform, and for filling the lined container, it will beunderstood that, if desired, it may be incorporated into known packagingmachinery by suitable modification thereof to the end that a compact andhigh speed assembly for container forming, container lining, containerfilling, and container sealing may be used.

As shown, one satisfactory form of manually operable, inexpensive andmechanically simple apparatus may include a stationary base plate uponwhich a pair of guide rods 31 and 32 are mounted for support andguidance of a carriage 33. Adjacent their upper ends, the guide rods arebraced by a transverse bar 34 and at a suitable location above theuppermost retracted position of the carriage, a stationary housing 35for a rotatable stub shaft journalled therein, is securely mounted upona guide rod.

Extending from the outer end of the stub shaft is an actuating member orlever 36 normally held in fully retracted position as by a torsionspring 37 fixed at one end to an abutment on the stationary housing andat the other end to the movable handle. One or more tension springs 38fixed at one end to the stationary bar 34 and at the other end to themovable carriage 33, serve to hold the carriage in retracted positionwhere it is available for ready insertion or removal of the linerpreform and container with respect to the mandrel.

Projecting from the carriage is a hollow metallic mandrel 22, rigidlyatfixed as by bolts or welds (not shown) to the carriage 33 at a centrallocation thereof, and adapted for reciprocable movement in apredetermined path as the carriage moves along the guide rods. A

framework comprising pairs of spaced posts' 40, 41; 42, 43; and 44, 45,is rigidly mounted upon the base plate 30 in surrounding relation to twosides and one end of the path of mandrel movement and with the upperends of the posts terminating in a plane slightly below the bottom ofthe fully retracted mandrel. Disposed between posts 40 and 41 is apressure applying member, preferably a cylindrical, rubber-like roll 46,rotatably -on the mandrel. Moreover, any suitable switching means may beemployed to apply and cut off current to the 1 ment of the reciprocablecarriage 33.

'the mandrel.

journalled in the posts and having a diameter which is sufiicient to'cause the surface of the roll to press firmly against an outer side ofcontainer 23 as the mandrel is moved past the roll 46. Likewise, apressure applying member, such as roll 47 mounted between posts 42 and43 and a pressure applying member, such as a shorter roll 48, mountedbetween posts 44 and 45, are provided for pressing firmly againstanother outer side and an end respectively of the container during themandrel movement.

Located between the respective posts and disposed in the path ofmovement of the mandrel is a platen 50, preferably of a fiat rubberlikematerial and resiliently mounted upon compression springs 51 whichsurround guide rods mounted at one end upon base plate 30 and havinglimiting stops 52 at the other end to limit the upward movement of theplaten. This platen is adapted to press firmly against the lower side ofthe container when the mandrel is lowered to its bottommost position.

Mounted upon the face of carriage 33 is a master pressure applying plate60 pivotable about hinge 61 and having a boss 62 on its upper face.Pivotally secured upon the boss 62 and upon a pin 63 located at anintermediate point on handle 36 is a link 64 connecting the handle andthe master plate 60. The plate 60 preferably is fiat and has a surface65 of rubberlike material adapted to press upon the upper side ofcontainer 23 when installed upon As will thus be apparent, when handle36 is in normal retracted position under the influence of spring 37, themaster pressure applying plate likewise is in raised position withrespect to mandrel 22, and the perform and container may be readilyinstalled upon or removed from the mandrel.

Referring now to Figs. 4 and 5, the mandrel may have any suitablepolysided configuration, but as shown herein is of parallepiped shapewith an undercut portion 66 adjacent its mounting upon the carriage 33.As a result of this undercut portion, the extended open end of the linerI preform is not pressed into close contact with the heated mandrel,thus permitting the wax layer of the liner to remain unmelted at itsextreme open end. Disposed within the metallic mandrel on all sides andat the outer end thereof is a high resistance electrical coil 67 embedded in a ceramic or other suitable heat resistant electricalinsulator 68 and connected to an electrical conductor 69 leading throughcarriage 33. This conductor .may lead to any suitable circuit forming nopart of the present invention and which may apply current to the coil 67under control of a conventional powerstat which varies voltage tomaintain a predetermined surface temperature mandrelat desired times.

At its outer end the hollow mandrel is provided with a plurality ofsmall apertures 70 through which a gaseous medium under pressure may beexpelled. Leading into the mandrel through carriage 33 is a hoseconnection 71 .suitably attached to a pressure source which may becontrolled by any suitable valve (not shown) adapted to be actuated atthe time the liner is completely sealed within the container in order tostrip the container from the retracted mandrel and then to be actuatedto close off the .source, until the stripping of the subsequentcontainer is desired. It will be understood that both the conductor 69and hose 71 are mounted for partaking of the move- The operation of theapparatus will now be noted from a comparison of Figs. 1, 6 and 7. Withthe mandrel,

. carriage and master pressure plate in the fully retracted position ofFig. 1, the metallic liner preform 21 is positioned endwise upon themandrel and with its most difiicult to seal side seam, as seen at 24, inposition below the mandrel surface due to the undercut 66 of thatmandrel. With heat being appliedto mandrel 22, the handle 36 is lowered,whereupon plate 60 isbrought into contact with the upper side ofcontainer 23 whiehin turn presses against the side seam 24 of thepreform which in turn presses its metallic inner surface 11 against themetallic surface of mandrel 22.- This pressure by master plate 60 iscontinuously applied during the entire lining operation with the resultthat not only is the tissue layer of the liner securely bonded to theinner surface of the container, but also the m'eta'l to-met'al seal atseam 24 is securely bonded by virtue-of the extended application ofpressure. However, despite this prolonged application of pressure of ametallic foil against a hot metallic surface, no scarring or galling ofthe lineroccurs when the container is removed due to the above'describedlineembedded feature of the liner material.

After lowering the plate 60 into operative contact with the upper sideof container 23, further pressure'upon handle 36 through its hingedconnection with carriage 33 begins to force that carriage downwardlyagainst-the' action of springs 38. As the carriage moves downwardly,carrying the mandrel therewith, pressure rolls 46 and 47 force the sidesof the container into contact with the liner preform and at the sametime the pressure roll 48 forces the end of the container into contactwith the end of that preform. It will be noted that these rolls provideonly a line contact with the sides and end of the container, but thattwo such phases of contact result, during both the downward movement andduring the subsequent upward movement. At the time when rolls 46, 47 and48 complete their first passage across the surfaces of the container,the continued pressure of handle 36 (Fig. 7) forces the mandrel intocontact with the platen 50. Further movement of the mandrel downwardlycompresses springs 51, causing the underside of the container to beforced against the liner and that liner, in turn, to be forced againstthe underside of the hot mandrel. After holding the handle 36 in fullydepressed position for the time necessary to bond the liner to theunderside of the container, the handle is then lifted upwardly, beingassisted by the torsion spring 37 and by the tension springs 38. Duringits upward movement, the second phase of pressure application by rolls46, 47 and 48 occurs, the application of pressure by master plate 60having been continuous throughout the operation.

When the mandrel carriage and handle are returned to the position ofFig. 1, pressure fluid is then released through hose 71 and the linedcontainer is automatically stripped from the mandrel without tearing ormarring of the metallic surface of the liner.

It has been found that by employing the described apparatus inconjunction with the Reyseal liner, a superior appearance of linedcontainer is secured. The entire inner surface of the container issubstantially smooth, without wrinkles and without torn surfaces. Atight metal-tometal seal along the side and end seams of the containerresults, which makes the lined container particularly well suited forcontaining liquids and foodstuffs and for later hermetic sealingfollowing filling of that container.

Having thus described the invention and having shown one form ofapparatus embodying the same, it will be apparent that variousmodifications can be made, without departing from my invention, Itherefore, do not wish to be limited to the particular modification asshown and contemplate by the appended claims to cover any suchmodifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. Apparatus for securing a heat-scalable liner in a containercomprising, a movable mandrel for receiving a liner preform and adetached container substantially completely surrounding said preform,said preform and container being insertable endwise upon said mandreland removable endwise therefrom, a pressure plate member for pressingsaid liner andcontainer together against a first side of said mandreland for holding the same in contact during the lining operation, aresiliently mounted member for pressing said liner and containertogether against a second side of said mandrel opposite to said firstside thereof, means disposed adjacent the path of travel of said mandreland adapted to press said liner and container together against theremaining sides and one end of said mandrel during its movement into andfrom engagement with said resiliently mounted member, means for movingsaid mandrel, and means for applying heat to said mandrel thereby tosealsaid liner preform to said container.

2. Apparatus as defined in claim 1 including means normally holding saidmandrel in retracted position for ready insertion and removal of saidliner preform and container, said mandrel moving means being connectedto said pressure plate member for moving said mandrel against the actionof said mandrel retracting means.

3. Apparatus for securing a heat-sealable metallic liner in a containercomprising, in combination, a movable metallic mandrel for receiving aliner preform and a detached container substantially completelysurrounding said preform, said preform comprising a folded laminatedsheet having a metallic surface in contact with said metallic mandrel, abonding surface in contact with said container and an intermediate waxlayer between said metallic and bonding surfaces, and with said foldedpreform having an unsealed seam disposed along a first side of saidmandrel, said preform and container being insertable endwise upon saidmandrel and removable endwise therefrom, a pressure plate member forpressing said liner and container together against said first side ofsaid mandrel, and for holding the same in contact during the liningoperation, a resiliently mounted member for pressing said liner andcontainer together against a second side of said mandrel opposite tosaid first side thereof, means disposed adjacent the path of travel ofsaid mandrel and adapted to press said liner and container togetheragainst the remaining sides and one end of said mandrel during itsmovement into and from engagement with said resiliently mounted member,means for moving said mandrel and means for applying heat to saidmandrel thereby to melt said wax layer and to seal said bonding surfaceto said container and said seam to itself.

4. Apparatus as defined in claim 3 including a hollow mandrel having acontrolled source of pressure fluid connected thereto and apertures insaid mandrel end directed against the end of said lined containerthereon, whereby said container may be stripped from said mandrel bymeans of pressure fluid emerging from said apertures.

5. Apparatus for securing a heat-sealable liner in a containercomprising a framework having a carriage movably mounted thereon, amandrel rigidly mounted on said carriage for receiving a liner preformand a detached container substantially completely surrounding saidpreform, means normally holding said carriage and mandrel in a retractedposition, means mounted upon said framework and disposed in the path oftravel of said mandrel for pressing said liner and container togetheragainst three sides and one end of said mandrel, a pressure plate memberfor pressing said liner and container together against one side of saidmandrel and for forcing said carriage from said retracted positionthereby to carry said mandrel into contact with said means disposed inits path of travel, means for moving said pressure plate to cause travelof said movable carriage, means for retracting said pressure plate to aposition normally out of contact with said mandrel, and means forapplying heat to said mandrel thereby to seal said liner to saidcontainer.

6. Apparatus as defined in claim 5 wherein said means mounted upon saidframework for pressing said liner and container together against saidmandrel includes rotatably mounted rolls disposed adjacent the path ofmandrel travel and engageable by the sides and end of said container.

7. Apparatus as defined in claim 5 wherein said means mounted upon saidframework for pressing said liner and container together against saidmandrel includes a resiliently mounted platen disposed in the path ofmandrel travel and engageable by one side of said container.

8. Apparatus for securing a heat-sealable liner in a containercomprising a framework having a carriage movably mounted thereon, amandrel rigidly mounted on said carriage for receiving a liner preformand a detached container substantially completely surrounding saidpreform, means normally holding said carriage and mandrel in a retractedposition, means mounted upon said framework and disposed in the path oftravel of said mandrel for pressing said liner and container togetheragainst three sides and one end of said mandrel, a pressure plate memberhinged at one end to said carriage and adapted to press said liner anlcontainer together against one side of said mandrel, a carriageactuating lever mounted upon said framework and movable against theaction of said carriage retracting means, means connecting saidactuating lever to said pressure plate member whereby said pressureplate may engage said mandrel during the entire movement of saidcarriage, and means for applying heat to said mandrel thereby to sealsaid liner to said container. 7

9. Apparatus as defined in claim 8 including means interposed betweensaid actuating lever and framework for holding said lever and connectedpressure plate normally in retracted position.

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